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Gatherround
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<script src="https://code.jquery.com/jquery-3.1.0.min.js"></script> | |
<canvas id="canvas"></canvas> |
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function Vector(x, y, z) { | |
this.x = x || 0; | |
this.y = y || 0; | |
this.z = z || 0; | |
} | |
Vector.prototype = { | |
negative: function() { | |
return new Vector(-this.x, -this.y, -this.z); | |
}, | |
add: function(v) { | |
if (v instanceof Vector) return new Vector(this.x + v.x, this.y + v.y, this.z + v.z); | |
else return new Vector(this.x + v, this.y + v, this.z + v); | |
}, | |
subtract: function(v) { | |
if (v instanceof Vector) return new Vector(this.x - v.x, this.y - v.y, this.z - v.z); | |
else return new Vector(this.x - v, this.y - v, this.z - v); | |
}, | |
multiply: function(v) { | |
if (v instanceof Vector) return new Vector(this.x * v.x, this.y * v.y, this.z * v.z); | |
else return new Vector(this.x * v, this.y * v, this.z * v); | |
}, | |
divide: function(v) { | |
if (v instanceof Vector) return new Vector(this.x / v.x, this.y / v.y, this.z / v.z); | |
else return new Vector(this.x / v, this.y / v, this.z / v); | |
}, | |
equals: function(v) { | |
return this.x == v.x && this.y == v.y && this.z == v.z; | |
}, | |
dot: function(v) { | |
return this.x * v.x + this.y * v.y + this.z * v.z; | |
}, | |
cross: function(v) { | |
return new Vector( | |
this.y * v.z - this.z * v.y, | |
this.z * v.x - this.x * v.z, | |
this.x * v.y - this.y * v.x | |
); | |
}, | |
length: function() { | |
return Math.sqrt(this.dot(this)); | |
}, | |
unit: function() { | |
return this.divide(this.length()); | |
}, | |
min: function() { | |
return Math.min(Math.min(this.x, this.y), this.z); | |
}, | |
max: function() { | |
return Math.max(Math.max(this.x, this.y), this.z); | |
}, | |
toAngles: function() { | |
var phi = Math.atan2(this.y , this.x); | |
if(phi<0){ | |
phi = phi + Math.PI * 2; | |
} | |
return { | |
theta: Math.acos(this.z/this.length()), | |
phi: phi | |
}; | |
}, | |
angleTo: function(a) { | |
return Math.acos(this.dot(a) / (this.length() * a.length())); | |
}, | |
toArray: function(n) { | |
return [this.x, this.y, this.z].slice(0, n || 3); | |
}, | |
clone: function() { | |
return new Vector(this.x, this.y, this.z); | |
}, | |
init: function(x, y, z) { | |
this.x = x; this.y = y; this.z = z; | |
return this; | |
} | |
}; | |
Vector.negative = function(a, b) { | |
b.x = -a.x; b.y = -a.y; b.z = -a.z; | |
return b; | |
}; | |
Vector.add = function(a, b, c) { | |
if (b instanceof Vector) { c.x = a.x + b.x; c.y = a.y + b.y; c.z = a.z + b.z; } | |
else { c.x = a.x + b; c.y = a.y + b; c.z = a.z + b; } | |
return c; | |
}; | |
Vector.subtract = function(a, b, c) { | |
if (b instanceof Vector) { c.x = a.x - b.x; c.y = a.y - b.y; c.z = a.z - b.z; } | |
else { c.x = a.x - b; c.y = a.y - b; c.z = a.z - b; } | |
return c; | |
}; | |
Vector.multiply = function(a, b, c) { | |
if (b instanceof Vector) { c.x = a.x * b.x; c.y = a.y * b.y; c.z = a.z * b.z; } | |
else { c.x = a.x * b; c.y = a.y * b; c.z = a.z * b; } | |
return c; | |
}; | |
Vector.divide = function(a, b, c) { | |
if (b instanceof Vector) { c.x = a.x / b.x; c.y = a.y / b.y; c.z = a.z / b.z; } | |
else { c.x = a.x / b; c.y = a.y / b; c.z = a.z / b; } | |
return c; | |
}; | |
Vector.cross = function(a, b, c) { | |
c.x = a.y * b.z - a.z * b.y; | |
c.y = a.z * b.x - a.x * b.z; | |
c.z = a.x * b.y - a.y * b.x; | |
return c; | |
}; | |
Vector.unit = function(a, b) { | |
var length = a.length(); | |
b.x = a.x / length; | |
b.y = a.y / length; | |
b.z = a.z / length; | |
return b; | |
}; | |
Vector.fromAngles = function(theta, phi) { | |
return new Vector(Math.cos(theta) * Math.cos(phi), Math.sin(phi), Math.sin(theta) * Math.cos(phi)); | |
}; | |
Vector.randomDirection = function() { | |
return Vector.fromAngles(Math.random() * Math.PI * 2, Math.asin(Math.random() * 2 - 1)); | |
}; | |
Vector.min = function(a, b) { | |
return new Vector(Math.min(a.x, b.x), Math.min(a.y, b.y), Math.min(a.z, b.z)); | |
}; | |
Vector.max = function(a, b) { | |
return new Vector(Math.max(a.x, b.x), Math.max(a.y, b.y), Math.max(a.z, b.z)); | |
}; | |
Vector.lerp = function(a, b, fraction) { | |
return b.subtract(a).multiply(fraction).add(a); | |
}; | |
Vector.fromArray = function(a) { | |
return new Vector(a[0], a[1], a[2]); | |
}; | |
Vector.angleBetween = function(a, b) { | |
return a.angleTo(b); | |
}; | |
var util = { | |
norm: function (value, min, max) { | |
return (value - min) / (max - min); | |
}, | |
lerp: function (norm, min, max) { | |
return min + norm * (max - min); | |
}, | |
map: function (value, sourceMin, sourceMax, destMin, destMax) { | |
return this.lerp(this.norm(value, sourceMin, sourceMax), destMin, destMax); | |
}, | |
clamp: function (value, min, max) { | |
return Math.min(Math.max(value, min), max); | |
}, | |
distance: function (x0, y0, x1, y1) { | |
var dx = x0 - x1; | |
var dy = y0 - y1; | |
return Math.sqrt(dx * dx + dy * dy); | |
}, | |
randomRange: function (min, max) { | |
return min + Math.random() * (max - min); | |
}, | |
randomInt: function (min, max) { | |
return Math.floor(min + Math.random() * (max - min + 1)); | |
}, | |
degreesToRads: function (degrees) { | |
return degress / 180 * Math.PI | |
}, | |
radsToDegrees: function (radians) { | |
return radians * 180 / Math.PI; | |
}, | |
roundToPlaces: function (value, places) { | |
var mult = Math.pow(10, places); | |
return Math.round(value * mult) / mult; | |
}, | |
roundNearest: function (value, nearest) { | |
return Math.round(value / nearest) * nearest; | |
} | |
}; | |
var canvas = document.getElementById("canvas"); | |
var context = canvas.getContext("2d"); | |
var width = canvas.width = window.innerWidth; | |
var height = canvas.height = window.innerHeight; | |
var CenterX = width / 2; | |
var CenterY = height / 2; | |
var dotImageList = []; | |
for(var i = 1; i <= 4; i++){ | |
var dotImage = new Image(); | |
dotImage.src = "http://wximg.gtimg.com/tmt/coding-math/dist/img/gatherround/dot" + i + ".png"; | |
dotImageList.push(dotImage); | |
} | |
var sphereRad = 130; | |
var fLen = 300; | |
var maxParticle = 400; | |
var turnSpeed = 0.005; | |
var particles = []; | |
var Particle = function (add) { | |
var theta; | |
if (add === true) { | |
theta = Math.PI / 2; | |
} else { | |
theta = Math.random() * Math.PI; | |
} | |
this.distPos = { | |
theta: theta, | |
phi: 2 * Math.random() * Math.PI | |
}; | |
this.distPos.x = sphereRad * Math.sin(this.distPos.theta) * Math.cos(this.distPos.phi); | |
this.distPos.y = sphereRad * Math.sin(this.distPos.theta) * Math.sin(this.distPos.phi); | |
this.distPos.z = sphereRad * Math.cos(this.distPos.theta); | |
this.distVec = new Vector(this.distPos.x, this.distPos.y, this.distPos.z); | |
this.unitVec = this.distVec.unit(); | |
var startMult = 1 + Math.random() * 2; | |
this.startVec = this.distVec.multiply(startMult); | |
this.x = this.startVec.x; | |
this.y = this.startVec.y; | |
this.z = this.startVec.z; | |
this.veloRate = 1 + Math.random() * 1; | |
this.velo = this.unitVec.negative().multiply(this.veloRate); | |
this.finalVelo = 0; | |
this.m = fLen / (fLen - this.z); | |
this.age = this.life = 50 + Math.floor(Math.random() * 500); | |
this.proj = {}; | |
this.turnAngle = 0; | |
this.wanderTime = 200; | |
this.radius = 1 + Math.random() * 3; | |
var colorRandom = Math.floor(Math.random() * 4); | |
if (colorRandom === 0) { | |
this.img = dotImageList[0]; | |
this.color = "rgba(70,255,140,"; | |
} else if(colorRandom === 1){ | |
this.img = dotImageList[1]; | |
this.color = "rgba(90,90,90,"; | |
} else if(colorRandom === 2){ | |
this.img = dotImageList[2]; | |
} else if(colorRandom === 3){ | |
this.img = dotImageList[3]; | |
} | |
}; | |
Particle.prototype.update = function () { | |
this.nowPos = new Vector(this.x, this.y, this.z); | |
this.nowPosUnit = this.nowPos.unit(); | |
if (this.wanderTime > 0 && this.nowPos.length() > (sphereRad * 1.2)) { | |
this.wanderTime--; | |
this.velo.x += 0.1 * (Math.random() * 2 - 1); | |
this.velo.y += 0.1 * (Math.random() * 2 - 1); | |
this.velo.z += 0.1 * (Math.random() * 2 - 1); | |
this.x = this.x + this.velo.x; | |
this.y = this.y + this.velo.y; | |
this.z = this.z + this.velo.z; | |
this.op = util.map(this.nowPos.length(), sphereRad, this.startVec.length(), 1, 0); | |
} | |
else if (this.nowPos.length() > sphereRad) { | |
if(this.finalPos ===0){ | |
this.finalPos = this.nowPosUnit.multiply(sphereRad); | |
} | |
if(this.finalVelo === 0){ | |
this.finalVelo = this.nowPosUnit.negative().multiply(this.veloRate); | |
} | |
this.x = this.x + this.finalVelo.x; | |
this.y = this.y + this.finalVelo.y; | |
this.z = this.z + this.finalVelo.z; | |
this.op = util.map(this.nowPos.length(), sphereRad, this.startVec.length(), 1, 0); | |
} | |
else { | |
this.op = this.life / (this.age / 2); | |
this.turnAngle = (this.turnAngle + turnSpeed) % (Math.PI * 2); | |
var cosAngle = Math.cos(turnSpeed); | |
var sinAngle = Math.sin(turnSpeed); | |
this.x = cosAngle * this.nowPos.x + sinAngle * this.nowPos.z; | |
this.z = -sinAngle * this.nowPos.x + cosAngle * this.nowPos.z; | |
this.y = this.nowPos.y; | |
this.life--; | |
} | |
this.m = fLen / (fLen - this.z); | |
}; | |
function loop() { | |
context.clearRect(0, 0, width, height); | |
if (particles.length < maxParticle) { | |
var p = new Particle(); | |
particles.push(p); | |
} | |
for (var i = 0; i < particles.length; i++) { | |
var p = particles[i]; | |
if (p.life === 0) { | |
particles.splice(i, 1); | |
var p = new Particle(); | |
particles.push(p); | |
} | |
p.update(); | |
if (p.m > 0) { | |
context.save(); | |
context.globalAlpha = p.op; | |
context.drawImage(p.img,p.x * p.m + CenterX, CenterY - p.y * p.m,p.radius*p.m*2,p.radius*p.m*2); | |
context.restore(); | |
// context.fillStyle = p.color + p.op + ")"; | |
// context.beginPath(); | |
// context.arc(p.x * p.m + CenterX, CenterY - p.y * p.m, p.radius * p.m, 0, Math.PI * 2); | |
// context.fill(); | |
} | |
} | |
requestAnimationFrame(loop); | |
} | |
loop(); |
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* { | |
margin: 0; | |
padding: 0; | |
} | |
body { | |
width: 100%; | |
height: 100%; | |
background: #212020; | |
overflow: hidden; | |
} |
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